Module Rdf_sparql

module Rdf_sparql: sig .. end

Sparql queries.

Error handling

type error =

`\|`	`Parse_error of Rdf_loc.loc * string`
`\|`	`Value_error of Rdf_dt.error`
`\|`	`Eval_error of Rdf_sparql_eval.error`
`\|`	`Algebra_error of Rdf_sparql_algebra.error`
`\|`	`Not_select`
`\|`	`Not_ask`
`\|`	`Not_construct`
`\|`	`Not_describe`

exception Error of error

val string_of_error : error -> string

Parsing and printing Sparql queries

type query = Rdf_sparql_types.query

val parse_from_string : string -> query

val parse_from_file : string -> query

val string_of_query : query -> string

Executing queries

Solutions

type solution

val get_term : solution -> string -> Rdf_node.node

get_term solution varname returns the Rdf_node.node bound to varname in the solution.
Raises Not_found if the variable is not bound.

val is_bound : solution -> string -> bool

is_bound solution varname returns whether the given variable name is bound in the solution.

val solution_fold : (string -> Rdf_node.node -> 'a -> 'a) -> solution -> 'a -> 'a

solution_fold f sol acc is f var1 term1 (f var2 term2 (...) acc), folding over the bindings of the solution.

val solution_iter : (string -> Rdf_node.node -> unit) -> solution -> unit

solution_iter f solution calls f on each pair (varname, term) of the solution.

Querying

type query_result =

`\|`	`Bool of bool`
`\|`	`Solutions of solution list`
`\|`	`Graph of Rdf_graph.graph`

val execute : ?graph:Rdf_graph.graph ->
       base:Rdf_uri.uri ->
       Rdf_ds.dataset -> query -> query_result

execute ~base dataset q executes the sparql query q on dataset, using base as base uri. The form of the result depends on the kind of query:

Select queries return a Solution solutions
Ask queries return a Bool bool
Construct queries return Graph g.
Describe queries return a description graph.

For Construct and Describe queries, if a graph is provided, it is filled and the same graph is returned; else a new graph (in memory) is created, filled and returned. If the graph is created, it uri is the base uri provided.

Warning: Describe queries are not implemented yet.
Raises Error in case of error.

Convenient functions for querying

val select : base:Rdf_uri.uri ->
       Rdf_ds.dataset -> query -> solution list

Execute the given SELECT query.
Raises Not_select is the query is not a SELECT.

val construct : ?graph:Rdf_graph.graph ->
       base:Rdf_uri.uri -> Rdf_ds.dataset -> query -> Rdf_graph.graph

Execute the given CONSTRUCT query.
Raises Not_construct is the query is not a CONSTRUCT.

val ask : base:Rdf_uri.uri -> Rdf_ds.dataset -> query -> bool

Execute the given ASK query.
Raises Not_ask is the query is not a ASK.

val describe : ?graph:Rdf_graph.graph ->
       base:Rdf_uri.uri -> Rdf_ds.dataset -> query -> Rdf_graph.graph

Execute the given DESCRIBE query.
Raises Not_describe is the query is not a DESCRIBE.

Predefined functions

These are the functions named by an URI, see details here.

type uri_fun = Rdf_dt.value list -> Rdf_dt.value

A function takes a list of values and return a value.

val uri_funs : unit -> uri_fun Rdf_uri.Urimap.t

val add_uri_fun : Rdf_uri.uri -> uri_fun -> unit